Role of translational and vibrational energy in the dissociative chemisorption of methane on Pd {110}

Dissociative adsorption of methane has been investigated on Pd{110} by usin g molecular beam surface scattering. The initial sticking probability has b een determined in the translational energy range of 7-95 kJ/mol and at sele cted vibrational energies from 300 to 700 K. The measured initial sticking probability is found to increase strongly with both translational and vibra tional energy of CH4 Molecules. The activation of the dissociative chemisor ption of CH4 induced by the vibrational energy is shown to depend on the tr anslational energy and is attributed to the excitation of the bending modes of the incident molecule. We have also performed molecular dynamics simula tions to investigate the dissociation mechanism theoretically. The simulati ons clearly demonstrate that an efficient energy transfer occurs upon adsor ption between the translational and vibrational energies of the incident CH 4 molecule, which thereby facilitates the deformation of the molecular stru cture of CH4 resulting in dissociation. (C) 2001 Elsevier Science B.V. All rights reserved.